134 W. M. GRAHAM — RESULTS OBTAINED FROM A MONTHLY EXAMINATION 



At Lagos this species was founrl in the following Sanitary Divisions and 

 Districts of the township : — 



Division A ... Districts C, E., Q., S. 



B ... „ K., M. 



C ... „ H. 



D ... „ H., I., M. 



It may be noted that these Districts are mostly situated on that edge of the 

 island having the lowest elevation above sea-level. 



Other Larvte. 

 Chironomus (3 species). 



Sjijccies of this genus were present in 23'9 per cent, of the total water- 

 receptacles. These larvaj ("blood worms") are commonly found in pots and 

 barrels, and even in the large covered iron tanks used to collect rain-water from 

 the roof. 



Psychoda (2 species). 



Species of this genus were present in 6"1 per cent, of the receptacles. The 

 water in which they were found was usually extremely foul and often contained 



sewage. 



Drosophila (1 species). 



This species occurred in 1"0 per cent, of the receptacles examined, and a few 

 of the pupnj were reared for identification purposes. 



Ephemeridse. 



Larvaj were found in only 2 out of 1,043 receptacles examined. 



Crustacea. 

 Cyclops simillimus, Brady. 



This species was present in an average of 24"5 per cent, of all the water 

 receptacles examined. The fact is of considerable importance in relation to the 

 transmission of Guinea Worm, for natives frequently wash their feet in such 

 vessels, and if suffering from Guinea Worm would, dui'ing such ablutions, infect 

 any Cyclops present. Apparently therefore it is not necessary to go to water- 

 holes or public wells to find a source of Guinea Worm infection. 



This species of Cycloids was originally found by me in the Gold Coast, 

 where it was common in the borrow-pits along the railway. In Freetown Guinea 

 Worm is a rare disease, while at Accra it is a common one. It would therefore 

 be interesting to compare the distribution of this Cyclops in the two towns. 



